解旋酶
RNA解旋酶A
死盒子
核糖核酸
NS5B
生物
抄写(语言学)
化学
立体化学
病毒
病毒学
生物化学
结晶学
丙型肝炎病毒
基因
肝炎病毒
语言学
哲学
作者
Sujit Dutta,Garvita Gupta,Yook‐Wah Choi,Masayo Kotaka,Burtram C. Fielding,Jianxing Song,Yee‐Joo Tan
摘要
RNA helicases of the DEAD (Asp-Glu-Ala-Asp)-box family of proteins are involved in many aspects of RNA metabolism from transcription to RNA decay, but most of them have also been shown to be multifunctional. The DEAD-box helicase DDX5 of host cells has been shown to interact with the RNA-dependent RNA polymerase (NS5B) of HCV (hepatitis C virus). In the present study, we report the presence of two independent NS5B-binding sites in DDX5, one located at the N-terminus and another at the C-terminus. The N-terminal fragment of DDX5, which consists of the first 305 amino acids and shall be referred as DDX5-N, was expressed and crystallized. The crystal structure shows that domain 1 (residues 79–303) of DDX5 contains the typical features found in the structures of other DEAD-box helicases. DDX5-N also contains the highly variable NTR (N-terminal region) of unknown function and the crystal structure reveals structural elements in part of the NTR, namely residues 52–78. This region forms an extensive loop and an α-helix. From co-immunoprecipitation experiments, the NTR of DDX5-N was observed to auto-inhibit its interaction with NS5B. Interestingly, the α-helix in NTR is essential for this auto-inhibition and seems to mediate the interaction between the highly flexible 1–51 residues in NTR and the NS5B-binding site in DDX5-N. Furthermore, NMR investigations reveal that there is a direct interaction between DDX5 and NS5B in vitro.
科研通智能强力驱动
Strongly Powered by AbleSci AI